The mechanism of action of androgens will be studied on the mouse kidney. In these experiments, Beta-glucuronidase will be studiid since it is one of the best mapped eukaryotic genes. We will determine whether the Gur locus regulates the rate of Beta-glucuronidase messenger RNA synthesis from the structural gene. To accomplish this, Beta-glucuronidase messenger RNA will be isolated and a cDNA probe prepared. Androgen binding protein is the only Sertoli cell secretory product which has been isolated to homogeneity. A radioimmunoassay has been developed which will be used to study the physiology and pathophysiology of Sertoli cell function in normal and Hre rats. In addition, the physical-chemical properties of ABP subunit will be determined. Their mechanism of synthesis and assembly will be elucidated. Preliminary studies have suggested that protein carboxyl methylase may be involved in sperm motility. The localization of this enzyme and its methyl acceptor protein substrates in spermatozoa from normal and abnormal animals will be examined. An attempt will be made to link this protein and/or its substrate with sperm motion.